<template>
    <div>
        <router-link
        tag="div"
        to="/"
        class="header-abs"
        v-show="showAbs">
        <div class="iconfont header-abs-back">&#xe624;</div>
        </router-link>
        <div
        class="header-fixed"
        v-show="!showAbs"
        :style="opacityStyle"
        >
        <router-link to="/">
            <div class="iconfont header-fixed-back">&#xe624;</div>
        </router-link>
        景点详情
        </div>
    </div>
</template>

<script>
    export default{
        name:'DetailHeader',
        data(){
          return{
            showAbs: true,
            opacityStyle: {
              opacity: 0
            }
          }
        },
        methods:{
            handleScroll () {
                const top = document.documentElement.scrollTop
                if (top > 60) {
                    let opacity = top / 140
                    opacity = opacity > 1 ? 1 : opacity
                    this.opacityStyle = { opacity }
                    this.showAbs = false
                } else {
                    this.showAbs = true
                }
            }
        },
        mounted () {
            window.addEventListener('scroll', this.handleScroll)
        },
        unmounted () {
            window.removeEventListener('scroll', this.handleScroll)
        }
    }

</script>

<style lang="stylus">
    @import '~styles/varibles.styl'
    .header-abs
      position: absolute
      left: .2rem
      top: .2rem
      width: .8rem
      height: .8rem
      line-height: .8rem
      border-radius: .4rem
      text-align: center
      background: rgba(0, 0, 0, .8)
      .header-abs-back
        color: #fff
        font-size: .4rem
    .header-fixed
      z-index: 2
      position: fixed
      top: 0
      left: 0
      right: 0
      height: $headerHeight
      line-height: $headerHeight
      text-align: center
      color: #fff
      background: $bgColor
      font-size: .32rem
      .header-fixed-back
        position: absolute
        top: 0
        left: 0
        width: .64rem
        text-align: center
        font-size: .4rem
        color: #fff

</style>